Systems often include some type of functionality for providing data management. Data management is concerned with providing a logical view of the data that is available in a system. Such a logical view is also referred to here as the “data model” for the system. Data management is also concerned with the underlying physical organization of the data in the system and the transformation between the logical view of the data and the underlying physical organization. In addition, data management is typically concerned with a query mechanism for retrieving data from the system, a frame structure for the data, and the optimization of queries based on various parameters.
One type of system is a wireless sensor network. A wireless sensor network typically include several nodes that communicate with one another over wireless communication links (for example, over radio frequency communication links). One or more of the nodes in the wireless sensor network incorporate (or are otherwise coupled to) a sensor. Such nodes are also referred to here as “wireless sensor nodes” or “sensor nodes.” Each sensor is capable of generating a value that, at any given point in time, is indicative of some physical attribute of interest. In one configuration, the sensor nodes are battery powered and have limited computational resources (for example, limited memory and processing capability).
One approach to providing data management in a sensor network employs techniques used in relational database management systems (RDBMS). In such an approach, sensor data generated by sensor nodes in the network are logically organized into tables. Relational algebra is used for specifying the behavior of the logical view of the sensor data. Such an RDBMS approach, however, may not be suitable in a wireless sensor network that makes use of sensor nodes that have limited resources (for example, power, memory, or processing capability).